Waveguide junction for sequentially lobing antenna



y 1961 P. 5. HACKER ETAL 2,993,179

WAVEGUIDE JUNCTION FOR SEQUENTIALLY LOBING ANTENNA Filed May 18, 1956 INVENTORS Philip S. Hacker and Ralph I. Houser.

United States Patent 2,993,179 WAVEGUIDE JUNCTION FOR SEQUENTIALLY LOBING ANTENNA Philip S. Hacker and Ralph I. Hauser, Glen Burnie, Md., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed May 18, 1956, Ser. No. 585,807 5 Claims. (Cl. 333-7) This invention relates to waveguide junctions and more particularly to a waveguide junction adapted to direct wave energy from a main transmission line to a plurality of separate output transmission lines in sequence.

While not limited thereto, one application of. the present invention is to control the transfer of wave energy to or from a plurality of antenna elements which are mounted in spaced relation in advance of a parabolic or directional antenna. The arrangement is such that as wave energy is sequentially applied to the spaced antenna elements the direction of radiation from the antenna is periodically shifted at a predetermined rate while following or tracking a single target. In a system of this sort the antenna lobes are switched periodically and the direction of the target is determined by comparing signals received at the various lobe positions. Although the present invention is not concerned with the entire antenna arrangement, a full and detailed description of a sequentially lobing antenna may be had by reference to US. Patent No. 2,627,020, issued January 27, 1953, to W. S. Parnell and J. W. Taylor, Jr.

In addition to the tracking action of the aforesaid antenna, it is often necessary in radar applications to perform a search function during which time the radiated beam from the antenna must scan a large sector of space in an attempt to locate a target. During a search function, it is necessary to apply wave energy to only one of the antenna elements to the exclusionof all of the others.

It is a primary object of the present invention to provide a new and improved waveguide switch.

More specifically, it is an object of the invention to provide a sequence waveguide switch whichcan bemade to selectively feed wave energy to one of a plurality of output waveguides whereby a radar antenna, for example, may be switched from a tracking function to-asearch function.

The above and other objects and features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form a part of this specification and in which:

FIGURE 1 is a top view of one embodiment of the invention; and

FIG. 2 is a side view of the embodiment of the invention shown in FIG. 1.

Referring to FIG. 1, the embodiment of the invention 7 shown comprises four rectangular. waveguide sections 10, 12, 14 and 16 having their axes mutually perpendicular in a common plane and intersecting at a common point 18. As shown, the intersection of the four waveguide sections forms a common junction area 20 into which each of the waveguide sections opens; The four is directed into junction area 20 by means of a silver probe 24 embedded in a Teflon casing 26.

Slots 28 extending through all but the top wall of each of the waveguide sections 10-16 are located at points equidistant from junction point 18. Extending into the ice slots 28 is an annular cup-shaped member 30 which is adapted for rotation on an axle 32. The cup-shaped member 30 has three openings or slots 34, 36 and 38 spaced around its outer periphery at degree intervals. Each of the slots has a width approximately equal to the width of the waveguide sections 10-16 so that as the cupshaped member 30 rotates only one of the waveguide sections 10-16 will be opened to wave energy by one of the slots 34-38 while all of the other sections are short circuited. Furthermore, the open waveguide section will advance sequentially around junction point 18 as the member 30 is rotated to feed wave energy to each of the antenna feeds 1-4 in sequence. If the slots 28 in waveguide sections 10-16 are correctly placed the voltage standing wave ratio of the junction can be made less than 1.10; and, since the junction is symmetrical, the shorts can be rotated to allow the various arms to be sequentially opened, one at a time, without disturbing the matched condition of the junction.

When it becomes necessary for the radar system to switch from a tracking function to search function, wave energy should pass out only one of the waveguide sections 10-16. In this case we will assume that the wave energy should pass out section 10 to antenna feed 1 during a search function. For this purpose, a Waveguide section 40 is connected between input waveguide 22 and output waveguide section 10. Normally a probe 42, actuated by a solenoid 44, places a short circuit in the waveguide section 40; and, consequently, wave energy in section 22 passes into junction area 20 from whence it passes to the four antenna feeds via sections 10-16. When it is necessary to switch from a tracking function to a search function, probes 46 and 48, actuated by solenoids 50 and 52 respectively, are inserted into waveguide I sections 22 and 10; and probe 42 is withdrawn from waveguide section 40. Consequently, wave energy will be directed through waveguide section 40 to section 10 and hence to antenna feed 1. If the probes 46 and 48 are properly positioned with respect to their adjacent T-junctions, the circuit will be reflectionless; but the path taken by the wave energy will change. Energy coming down the main feed line 22 reflects from probe 46 and enters section- 40 connecting the sections 22 and 10. In section 10 it reflects from probe 48 and continues to feed 1 only. The sequential switch has been bypassed, but may still remain running while energy is entering and leaving the antenna through only the one feed No. 1. 5

Although the invention has been described in connection with a certain specific embodiment, it should be readily apparent to those skilled in the art that various changes in form and arrangement of parts can be made to suit requirements without departing from the spirit and scope of the invention.

We claim as our invention:

1. In combination, a waveguide junction comprising four rectangular waveguide sections having their axes mutually perpendicular to each other in a common plane and intersecting at a common point, said sections being joined together to form a common enclosed junction area into which each of said sections opens, a rotatable circular shutter having three equally spaced apertures around the periphery thereof for sequentially opening said waveguide sections one at a time to allow passage ofwave energy while simultaneously short circuiting the other three sections at points equidistant from said common junction, means including a main wave energy transmission line for conducting wave energy into said enclosed junction area, a second wave energy transmission line connecting said main transmission line to one of said four waveguide sections at a point thereon that isfurther from said common junction than the adjacent periphery of said shutter, means for normally short circuiting said second wave energy transmission line to direct wave energy from the main transmission line to said junction area from whence it is sequentially conducted to said four sections, and means for selectively shorting said main transmission line and said one waveguide section between said junction area and said second transmission line to direct wave energy from said main transmission line through the second transmission line to said one waveguide section.

2. In combination, a waveguide junction comprising four rectangular waveguide sections having their axes mutually perpendicular to each other in a common plane and intersecting at a common point, said sections being joined together to form a common enclosed junction area into which each of said sections opens, slots in said sections extending perpendicular to said common plane and spaced equidistant from said common point, a cup-shaped shutter rotatable about an axis extending through said common point, said shutter having a generally circular base and a flange extending outwardly from the planeof said base into said slots, apertures equally spaced around said flange for sequentially opening said waveguide sections one at a time to allow passage of wave energy while simultaneously short circuiting the other sections at points equidistant from said common junction, means including a main wave energy transmission line for conducting wave energy into said enclosed junction, and means for selectively blocking conduction of wave energy into said enclosed junction and for simultaneously directing the Wave energy in said transmission line into a single one of said waveguide sections at a point thereon that is further from said common junction than said slot of said waveguide sections around said common junction while.

leaving the fourth section open to wave energy, said 1atter-mentioned means being adapted to sequentially advance the open section around said junction, means in-- cluding a main wave energy transmission line forconducting wave energy into said junction, and means for selectively blocking conduction of wave energy into said junction and for simultaneously directing wave energy in said transmission line into a single one of said waveguide sections at a point thereon that is further from said common junction than the adjacent periphery of said shutter.

4. In combination, a waveguide junction comprising four rectangular waveguide sections having their axes mutually perpendicular to each other in a common plane and intersecting at a common point, said sections being joined together to form a common enclosed junction area into which each of said sections opens, an annular cup-shaped member rotatable about an axis perpendicular to said common plane and passing through said common point, said annular member being located on said axis whereby it extends across the path of Wave energy in said waveguide sections, said annular member having openings in its outer circumference spaced degrees apart, means including a main wave energy transmission line for conducting wave energy into said junction, and means for selectively blocking conduction of wave energy into said junction and for simultaneously directing wave energy in said main transmission line into a single one of said waveguide sections at a point that is further from said junction than the adjacent periphery of said annular member.

5. In combination, a wave guide junction comprising a plurality of rectangular waveguide sections having their axes intersecting at a common point, said sections being joined together to form a common enclosed junction area into which'each of said sections opens, means for short circuiting all but one of said waveguide sections while simultaneously opening the remaining section to wave energy, said latter-mentioned means including a substantially cup-shaped member rotatable about an axis passing through said common point, said member and having an upwardly-extending annular flange around its periphery which extends across the path of wave energy in said waveguide sections, openings located in the annular flange of said member to permit wave energy to pass through successive sections of said plurality of wave guide sections as the member rotates about its axis, a main wave energy transmission line for conducting wave energy into said enclosed junction, and means for selectively blocking conduction of wave energy into said junction and for simultaneously directing wave energy in said main transmission line into a single one of said waveguide sections at a point thereon that is further from said enclosed junction than the adjacent periphery of said annular flange.

References Cited in the file of this patent UNITED STATES PATENTS I 2,549,721 Straus Apr. 17, 1951 2,757,341 Lundstrom July 31, 1956 FOREIGN PATENTS 597,217 Great Britain Ian. 21, 1948 

